Various different agents and methods of fire extinguishment are known and can be selected for a particular fire, depending upon its size and location, the type of combustible materials involved, etc. In fixed enclosures (e.g., computer rooms, storage vaults, telecommunications switching gear rooms, libraries, document archives, petroleum pipeline pumping stations, and the like), halogenated hydrocarbon fire extinguishing agents have traditionally been utilized. Such agents are not only effective but, unlike water, also function as "clean extinguishing agents," causing little, if any, damage to the enclosure or its contents.
The most commonly-used halogenated hydrocarbon extinguishing agents have been bromine-containing compounds, e.g., bromotrifluoromethane (CF.sub.3 Br, Halon 1301) and bromochlorodifluoromethane (CF.sub.2 ClBr, Halon 1211). Such bromine-containing halocarbons are highly effective in extinguishing fires and can be dispensed either from portable equipment or from an automatic room flooding system activated by a fire detector. However, the compounds have been linked to ozone depletion. The Montreal Protocol and its attendant amendments specified that Halon 1211 and 1301 production be discontinued (see, e.g., P. S. Zurer, "Looming Ban on Production of CFCs, Halons Spurs Switch to Substitutes," Chemical & Engineering News, page 12, Nov. 15, 1993).
Thus, there has developed a need in the art for substitutes or replacements for the commonly-used, bromine-containing fire extinguishing agents. Such substitutes should have a low ozone depletion potential; should have the ability to extinguish, control, or prevent fires or flames, e.g., Class A (trash, wood, or paper), Class B (flammable liquids or greases), and/or Class C (electrical equipment) fires; and should be clean extinguishing agents, i.e., be electrically non-conducting, volatile or gaseous, and leave no residue. Preferably, substitutes will also be low in toxicity, not form flammable mixtures in air, have acceptable thermal and chemical stability for use in extinguishing applications, and have short atmospheric lifetimes and low global warming potentials.
Various different fluorinated hydrocarbons have been suggested for use as fire extinguishing agents. For example, U.S. Pat. Nos. 5,040,609 and 5,115,868 (Dougherty et al.) describe a process for extinguishing, preventing, and controlling fires using a composition containing CHF.sub.3.
U.S. Pat. No. 5,084,190 (Fernandez) discloses a process for extinguishing, preventing, and controlling fires using a composition containing at least one fluoro-substituted propane.
U.S. Pat. No. 5,117,917 (Robin et al.) describes the use of completely fluorinated, saturated C.sub.2, C.sub.3, and C.sub.4 compounds in fire extinguishment.
U.S. Pat. No. 5,124,053 (Iikubo et al.) discloses the use of highly fluorinated, saturated C.sub.2 and C.sub.3 hydrofluorocarbons as fire extinguishing agents.
U.S. Pat. No. 5,250,200 (Sallet) describes an environmentally safe fire fighting technique which comprises directing a fire/flame extinguishing amount of an essentially zero ODP hydrofluoroalkane compound (other than a tetrafluoroethane or pentafluoroethane) onto a burning fire or flame.
Partially-fluorinated ethers have been suggested as chlorofluorocarbon alternatives (see, e.g., Yamashita et al., International Conference on CFC and BFC (Halons), Shanghai, China, Aug. 7-10, 1994, pages 55-58).
French Patent Publication No. 2,287,432 (Societe Nationale des Poudres et Explosifs) describes new partially-fluorinated ethers and a process for their preparation. The compounds are said to be useful as hypnotic and anesthetic agents; as monomers for preparing heat-stable, fire-resistant, or self-lubricant polymers; and in phyto-sanitary and phyto-pharmaceutical fields.
German Patent Publication No. 1,294,949 (Farbwerke Hoechst AG) describes a technique for the production of perfluoroalkyl-alkyl ethers, said to be useful as narcotics and as intermediates for the preparation of narcotics and polymers.
World Patent Publication No. WO 94/20588 (Nimitz et al.) discloses fluoroiodocarbon blends useful as chlorofluorocarbon and halon replacements.